The present disclosure herein relates to a tunable laser device and a method for manufacturing the same.
With the development of optical communication technology, the demand for laser devices having wavelength tunability is increasing. A typical tunable laser device includes an active layer that converts electrical energy into light energy to emit light, a plurality of reflector layers that reflects the generated light under predetermined resonance conditions, a cavity layer between the reflector layers, and a phase layer that adjusts a refractive index of a portion of the cavity layer to adjust a phase of the proceeding light and thereby to finely control an oscillation wavelength. Tunable laser devices are divided into a single integrated type in which the layers are disposed on one chip and an external cavity type in which the layers are disposed on two or more chips.
A typical oscillation wavelength is controlled by mounting a heater on the reflector layer or the phase layer to varying a wavelength by using a refractive index change due to a thermal effect. The wavelength tuning using the thermo-optic effect has an advantage of obtaining a stable wavelength change and wide wavelength tuning capability according to current applied to the heater. However, the wavelength tuning method using the thermo-optic effect has disadvantages in which power consumption is high, and a wavelength tuning rate is low.